Generation of pattern data with no overlapping or excessive distance between adjacent patterns

ABSTRACT

A device is disclosed for generating pattern data for unevenness that is randomly arranged on the surface of the reflective substrate of a reflective liquid crystal display device. The number of coordinates, a basic pitch, a movable range, and a dot diameter are entered from a data entry unit. An array generation unit regularly arranges base coordinates in two dimensions in accordance with the basic pitch. Coordinate displacement unit randomly displaces within the movable range at a portion of the basic coordinates to generate a multiplicity of displaced coordinates. Pattern generation unit arranges dot patterns with the dot diameter entered at each of the displaced coordinates generated to generate pattern data.

TECHNICAL FIELD

The present invention relates to a pattern generator for generatingpattern data that can be used for producing unevenness of the reflectingsurface of a reflector.

BACKGROUND OF THE ART

Power saving, compact, and lightweight liquid crystal displays are nowwidely used in portable terminal devices such as mobile telephones andPDAs (Personal Digital Assistants). These liquid crystal displaysinclude transmissive and reflective types. From the standpoint ofviewability, a transmissive type display in which a backlight isincorporated is now typically employed.

The use of a backlight, however, not only increases power consumption,but also stands in the way of smaller size and lighter weight.Therefore, there exists a need for a reflective liquid crystal displaythat has good viewability, particularly for portable terminal devices inwhich small size and light weight are critical and that use a battery asa power source. A known technique for improving the viewability of sucha reflective liquid crystal display involves forming unevenness on thereflecting surface of the reflective substrate to improve the reflectioncharacteristics of the reflective substrate. This technique is disclosedin, for example, Japanese Patent Publication No. 2,912,176.

In order to form random unevenness on the reflecting surface of areflective substrate in this way, pattern data must be generated inwhich dot patterns, which are to form depressions or protrusions, arerandomly distributed. As one example of a method of generating suchpattern data, a multiplicity of base coordinates that are regularlydistributed horizontally and vertically at a predetermined pitch may berandomly displaced and dot patterns then arranged at each of theserandomly displaced coordinates.

However, this simple and random displacement of the base coordinates atwhich dot patterns are arranged may result in problems such asoverlapping of neighboring dot patterns or excessive distance betweenneighboring dot patterns. Excessive distance between neighboring dotpatterns in particular results in a reflecting surface that reflects allincident light, which seriously degrades the reflection characteristicsof the reflective substrate.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a pattern generatorthat can generate pattern data in which overlap or excessive distancebetween randomly displaced dot patterns can be prevented.

It is another object of the present invention to provide a photomaskusing pattern data that have been generated by the above-describedpattern generator and a device for fabricating the same.

It is yet another object of the present invention to provide aray-reflecting member having excellent reflection characteristics and adevice for fabricating the same.

It is yet another object of the present invention to provide a liquidcrystal display having excellent viewability and a device forfabricating the same.

It is still another object of the present invention to provide aportable terminal device that is small and lightweight and that allows areduction of power consumption.

A first pattern generator according to the present invention generatespattern data in which a multiplicity of displaced coordinates aregenerated that are randomly arranged in two dimensions with a limitationon the arrangement of patterns to prevent overlap or excessive distancebetween patterns; and in which a predetermined pattern to formunevenness is arranged at at least a portion of or all of the generateddisplaced coordinates. Overlapping or excessive distance between thepredetermined pattern for unevenness can thus be prevented by means ofthe movable range.

The second pattern generator according to the present inventiongenerates pattern data in which a multiplicity of displaced coordinatesare generated that are randomly arranged in two dimensions with alimitation on the arrangement of patterns to prevent overlap orexcessive distance between patterns; and in which a predetermined dotpattern to form unevenness are arranged at at least a portion of or allof the generated displaced coordinates. Overlapping or excessivedistance between the predetermined dot patterns for unevenness can thusbe prevented by means of the movable range.

The third pattern generator according to the present invention generatespattern data in which a multiplicity of displaced coordinates aregenerated that are randomly arranged in two dimensions with a limitationon the arrangement of patterns to prevent overlap or excessive distancebetween patterns; and in which a predetermined line pattern to formunevenness are arranged at at least a portion of or all of the generateddisplaced coordinates. Overlapping or excessive distance between linepatterns can thus be prevented by means of the movable range.

The fourth pattern generator according to the present invention arrangesregularly a multiplicity of base coordinates in two dimensions accordingto a basic pitch entered and randomly displaces at least a portion ofthe multiplicity of base coordinates that has been arranged within amovable range to generate as data a multiplicity of displacedcoordinates, and arranges dot patterns with a predetermined dot diameterat each of the multiplicity of displaced coordinates to generate patterndata. Overlapping or excessive distance between dot patterns can thus beprevented by means of the movable range.

The fifth pattern generator according to the present invention regularlyarranges a multiplicity of base coordinates in two dimensions accordingto a basic pitch and randomly displaces at least a portion of themultiplicity of base coordinates that has been generated within amovable range to generate as data a multiplicity of displacedcoordinates, and arranges a line pattern with a predetermined line widthat each side of a plurality of predetermined polygons that take at leasta portion of the multiplicity of displaced coordinates that has beengenerated as vertices to generate pattern data. Overlapping or excessivedistance between line patterns can thus be predetermined by means of themovable range.

According to an embodiment of the present invention, a line pattern witha line width is arranged at each side of, as the polygons that take atleast a portion of the multiplicity of displaced coordinates asvertices, hexagons; and line patterns are randomly displaced from thebasic positions of each side of the hexagons to generate pattern data.Excellent reflection characteristics can thus be achieved when thepattern data that have been thus generated are applied to the formationof unevenness on the reflecting surface of the reflective substrate of areflective liquid crystal display.

Pattern data in which neighboring dot patterns do not overlap each othercan be generated by confirming that the basic pitch P, the movable rangeR, and the dot diameter D that are entered satisfy the relationship:P≧2R+D.

Pattern data in which neighboring line patterns do not overlap eachother can thus be generated by confirming that the basic pitch P, themovable range R, and the line width W that are entered satisfy therelationship: P≧2R+W.

In addition, by arranging base coordinates at positions such thateven-numbered rows of the base coordinate are displaced by one-half thebasic pitch in the column direction relative to odd-numbered rows of thebase coordinates, the base coordinates can be simply arranged at thepositions of the vertices of pseudo equilateral triangles.

Alternatively, the base coordinates can be randomly displaced by simpledata processing by displacing the base coordinates within a movablerange in accordance with random numbers that are generated by a randomnumber generation means.

Further, when applying generated pattern data to the formation ofunevenness on the reflecting surface of the reflective substrate of areflective liquid crystal display, excellent reflection characteristicscan be achieved by displacing the base coordinates such that thehalf-width of the distribution graph of the displacements of thedisplaced coordinates satisfies:0.3 P≦H≦0.9 P

In a photomask fabrication device according to the present invention,either light-transmitting portions or light-blocking portions are formedon a mask material using pattern data that have been generated by theabove-described pattern generator to form the light-transmittingportions or light-blocking portions of the photomask with dot patternsor line patterns that are randomly displaced within a movable range fromthe regular base coordinates. A photomask can thus be fabricated thatcan be used in forming unevenness having excellent reflectioncharacteristics on the reflecting surface of a reflective substrate of areflective liquid crystal display.

The photomask of the present invention is fabricated by theabove-described photomask fabrication device.

In the first photomask of the present invention, either alight-transmitting portion or a light-blocking portion is formed with adot pattern with a predetermined dot diameter at each of a multiplicityof displaced coordinates in which at least a portion of a multiplicityof base coordinates that have been regularly arranged according to abasic pitch have been randomly displaced within a movable range. Sincedot patterns that have been randomly displaced within a movable rangefrom the regular base coordinates are exposed by rays that havetransmitted through the light-transmitting portions, unevenness havingexcellent reflection characteristics can be formed on the reflectingsurface of the reflective substrate of a reflective liquid crystaldisplay.

In the second photomask of the present invention, either alight-transmitting portion or a light-blocking portion is formed with aline pattern with a line width on each side of a plurality of polygonsthat take as vertices at least a portion of a multiplicity of displacedcoordinates in which at least a portion of the multiplicity of basecoordinates that have been regularly arranged in accordance with a basicpitch are randomly displaced within a movable range. Since line patternsthat have been randomly displaced within a movable range from regularbasic positions are exposed by rays that have been transmitted by thelight-transmitting portions, unevenness having excellent reflectioncharacteristics can be formed on the reflecting surface of a reflectivesubstrate of a reflective liquid crystal display.

In the third photomask of the present invention, either alight-transmitting portion or a light-blocking portion is formed with aline pattern with a predetermined line width at each side of amultiplicity of hexagons that have been regularly arranged. Since linepatterns are exposed at the positions of each side of the hexagons bylight rays that have transmitted through the light-transmittingportions, unevenness having excellent reflection characteristics can beformed on the reflecting surface of the reflective substrate of areflective liquid crystal display.

The first reflector fabrication device according to the presentinvention forms unevenness on the reflecting surface of a reflector byphotoetching that employs the above-described photomask. Becauseunevenness of the reflecting surface of the reflector is formed with adot pattern or a line pattern that has been randomly displaced fromregular basic positions within a movable range, a reflective substrateof a reflective liquid crystal display having an excellent reflectioncharacteristic can be fabricated.

Specifically, at least a portion of the surface of a base member issubjected to photoetching by a photomask to form unevenness, and a metalthin-film is formed on the surface of the base member in which thisunevenness has been formed. Since the same unevenness as the surface ofthe base member can be produced on the surface of the metal thin-film, areflective substrate of a reflective liquid crystal display havingsuperior reflection characteristics can be easily fabricated throughphotoetching that employs a photomask.

The second reflector fabrication device according to the presentinvention receives pattern data that have been generated by theabove-described pattern generator and forms either depressions orprotrusions on the surface of a reflector with this pattern data. Sinceunevenness can be formed on the reflecting surface of a reflector withdot patterns or line patterns that have been randomly displaced within amovable range from regular basic positions, unevenness having excellentreflection characteristics can be formed on the reflecting surface ofthe reflective substrate of a reflective liquid crystal display.

Specifically, either depressions or protrusions are formed with patterndata on the surface of a metal thin-film of the surface of a base memberhaving a metal thin-film formed on at least a portion of its surface.Since unevenness is formed on the surface of the metal thin-film, thereflective substrate of a reflective liquid crystal display havingexcellent reflection characteristics can be easily fabricated throughphotoetching that does not employ a photomask.

The reflector according to the present invention is fabricated by theabove-described reflector fabrication device.

In the first reflector of the present invention, depressions orprotrusions are formed on a reflecting surface with dot patterns thathave been randomly displaced within a movable range from regular basicpositions.

In the second reflector according to the present invention, depressionsor protrusions are formed on a reflecting surface with line patternsthat have been randomly displaced within a movable range from regularbasic positions.

In the third reflector of the present invention, either depressions orprotrusions are formed with a line pattern with a predetermined linewidth on each side of a multiplicity of hexagons that are regularlyarranged. Accordingly, the third reflector can exhibit excellentreflection characteristics as the reflective substrate of a reflectiveliquid crystal display.

According to another aspect of the reflector of the present invention,unevenness is formed on the surface of a metal thin-film formed on thesurface of a base member. Accordingly, by use of the metal thin-film asthe picture element electrode of each liquid crystal picture element ofa reflective liquid crystal display, a reflective substrate of superiorstructure can be achieved.

Further, excellent reflection characteristics can be achieved as thereflective substrate of a reflective liquid crystal display, if theaverage pitch Pa of depressions or protrusions satisfies therelationship: 1.0≦Pa≦80 (μm), or, if the average pitch Pa and thehalf-width H of the pitch distribution graph of depressions orprotrusions satisfy the relationship 0.3 Pa≦H≦0.9 Pa.

A liquid crystal fabrication device according to the present inventionfabricates a reflective liquid crystal display in which a reflectorfabricated by the above-described reflector fabrication device is usedas the reflective substrate and a transparent substrate is arranged onthe surface of the reflective substrate through a liquid crystal layer.As a result, a reflective liquid crystal display can be fabricated inwhich the reflective substrate has excellent reflection characteristics.

Due to the excellent reflection characteristics of the reflectivesubstrate that can be achieved because the reflective substrate isconstituted by the above-described reflector, the liquid crystal displayof the present invention enables the display of an image with excellentviewability without the use of a backlight.

By using the liquid crystal display according to the present inventionto display data, the portable terminal device according to the presentinvention can display an image with excellent viewability without theuse of a backlight. Power consumption by a backlight is obviated, makingthe battery more compact and prolonging the time of use of the terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a pattern generator according to anembodiment of the present invention;

FIGS. 2A-2D is a schematic view of pattern generation process by thepattern generator of FIG. 1;

FIG. 3 is a distribution graph of the displacement pitch of displacedcoordinates;

FIGS. 4A and 4B is a schematic view showing pattern data by linepatterns;

FIG. 5 is a block diagram of a portable terminal fabrication device;

FIGS. 6A and 6B shows plan views of photomasks;

FIG. 7 is a vertical section of a frontal view showing the principleparts of a liquid crystal display;

FIG. 8 is a perspective view of a portable terminal device;

FIG. 9 is a flow chart illustrating pattern generation process by meansof a pattern generator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, pattern generator 100 according to anembodiment of the present invention comprises: data entry unit 11, entryconfirmation unit 12, array generation unit 13, random number generator14, coordinate displacement unit 15, pattern generation unit 16, patternoutput unit 17, and display unit 18.

Data entry unit 11 receives various data as input, such as switch data,coordinate numbers, basic pitch P, movable range R, and dot diameter D.

Switch data are binary data for setting whether pattern data are to begenerated as dot patterns or line patterns, as will be explainedhereinbelow. These data are displayed on display unit 18. For example,an operator may apply input by means of, for example, keyboard operationin accordance with input guidance such as “Please designate the dataformat: (1) dot patterns, (2) line patterns.”

The coordinate numbers are data of the number of base coordinates. Basicpitch P is data for arranging base coordinates at a regularly fixedspacing in the horizontal and vertical directions. Movable range R is amaximum of random displacement of the base coordinates. Dot diameter Dis the diameter of a dot pattern.

For the sake of simplicity, an example will be described in which thepattern data are generated as dot patterns. However, as will beexplained hereinbelow, pattern data may also be generated as line data,in which case line width W, which is the horizontal width of a linepattern, is entered instead of dot diameter D.

Entry confirmation unit 12 determines whether basic pitch P, movablerange R, and dot diameter D (or line width W) that have been enteredfrom data entry unit 11 satisfy the relationship:P≧2R+D(or W).

If entry confirmation unit 12 determines that the above-describedrelationship is not satisfied, display unit 18 displays a guidancemessage such as “The relationship between basic pitch P, movable rangeR, and dot diameter 15 D (or line width W) is improper. Shouldprocessing continue? Y/N.”

Array generation unit 13 regularly arranges a multiplicity of basecoordinates in two dimensions according to basic pitch P that has beenentered. However, in order to arrange the base coordinates at thepositions of vertices of pseudo equilateral triangles in patterngenerator 100 of this embodiment, the base coordinate are arranged suchthat the basic coordinates in even-numbered rows of the basiccoordinates are displaced by half the basic pitch P in the columndirection relative to odd-numbered rows of the basic coordinates, asshown in FIG. 2A.

Random number generator 14 generates random numbers. Coordinatedisplacement unit 15 randomly displaces each of the multiplicity of basecoordinates that have been regularly arranged by array generation unit13 using random numbers that are generated by random number generator14, thereby generating a multiplicity of displaced coordinates. In thiscase, the displacement is restricted within movable range R that hasbeen entered from data entry unit 11, as shown in FIGS. 2B and 2C.

More specifically, the range of these random numbers is known beforehandbecause pseudo random numbers are generated that circulate as asequential machine in pattern generator 100 of this embodiment. Tworandom numbers are generated for each of the multiplicity of basecoordinates, the first random number being multiplied by a predeterminedcoefficient to produce a displacement angle of from 0° to 360°. Acoefficient is then calculated such that the maximum value of the randomnumber is the maximum value of movable range R, and the second randomnumber is multiplied by this coefficient to produce a displacementdistance. A position that is distant from a base coordinate by exactlythe displacement distance is then rotated exactly the displacement anglefrom a reference direction, for example, in the row direction with thebase coordinate as center to produce a randomly displaced coordinate.

When generating displaced coordinates in a manner as described above,coordinate displacement unit 15 also generates a distribution graph ofdisplacement of the displaced coordinates as shown in FIG. 3 andcontrols displacement of the base coordinates such that the half-width Hand basic pitch P satisfy the relationship:0.3 P≦H≦0.9 P

Pattern generation unit 16 generates pattern data in which a dot patternwith dot diameter D is arranged at each displaced coordinate that isgenerated by coordinate displacement unit 15 to generate pattern data,as shown in FIG. 2D. Pattern output unit 17 outputs the pattern datathat have been generated by pattern generation unit 16. The data outputof pattern output unit 17 is executed as, for example, data-writing toFD (Floppy Disk) by means of FDD (Floppy Disk Drive) or transmittingdata online by means of an interface unit.

Dot patterns are not limited to circles as shown in FIG. 2D and may beof any separate, for example, ellipse or polygon such as triangle,quadrilateral, pentagon, and hexagon. Dot pattern data may be producedby arranging dot patterns at at least a portion of the displacedcoordinates produced by coordinate displacement unit 15.

When data generation based on line patterns is selected as describedabove, a predetermined line pattern with a line width W is arranged ateach side of a hexagon that takes as vertices six displaced coordinatesthat are positioned in the vicinity of one displaced coordinate, asshown in FIG. 4. Alternatively, a predetermined line pattern with a linewidth W may be arranged at all of the displaced coordinates generated bycoordinate displacement unit 15 to generate pattern data.

Furthermore, a line pattern with a line width W may be arranged at eachside of a plurality of predetermined polygons that take at least aportion of the displaced coordinates generated by coordinatedisplacement unit 15 as vertices to generate pattern data. Inparticular, FIG. 4B shows a case in which a line pattern with a linewidth W is arranged at each side of hexagons that take six displacedcoordinates around a single displaced coordinate as vertices.

FIG. 5 shows the constitution of photomask fabrication device 120 thatemploys pattern generator 100 of this embodiment, of reflectorfabrication device 130 that employs photomask fabrication device 120, ofliquid crystal fabrication device 140 that employs reflector fabricationdevice 130, and of portable terminal fabrication device 150 that employsliquid crystal fabrication device 140.

Photomask fabrication device 120 is a device for fabricating photomask200 based on pattern data that are generated by pattern generator 100and comprises pattern generator 100, pattern input unit 121,material-securing unit 122, and pattern-forming unit 123.

Pattern input unit 121 receives as input pattern data that have beengenerated by pattern generator 100. Material-securing unit 122 securesmask material 201 in position, and is, for example, a securing stage.Pattern-forming unit 123 forms light-transmitting portions 202 on maskmaterial 201 that is secured by material securing unit 122 byphotoetching using the pattern data and is, for example, an exposuredevice.

Photomask 200 is fabricated by photomask fabrication device 120 asdescribed in the foregoing explanation. In this photomask 200, as shownin FIG. 6A, light-transmitting portions 202 are formed with a dotpattern with dot diameter D at a multiplicity of displaced coordinatesthat are derived by randomly displacing, within movable range R, amultiplicity of base coordinates that have been regularly arrangedaccording to basic pitch P.

Reflector fabrication device 130 is a device that fabricates reflectivesubstrate 301, which is a reflector of liquid crystal display 300, usingphotomask 200 that has been fabricated by photomask fabrication device120. It comprises member-securing unit 131, member-etching unit 132, andmetal-film forming unit 133.

Member-securing unit 131 secures base member 302 of reflective substrate301 in a predetermined position and is constituted by, for example, asecuring stage. Member-etching unit 132 uses photoetching that employsphotomask 200 to form unevenness on the surface of base part 302 securedby member-securing unit 131 and is constituted by, for example, anexposure device. Metal-film forming unit 133 forms metal thin film 303on the surface of base part 302 on which unevenness has been formed bymember-etching unit 132 and is constituted by, for example, afilm-forming device.

A method of forming unevenness by photoetching includes a series ofphoto lithography processes consisting of resist forming process,exposure process using photomask 200, and development process, forinsulation film on the surface of member 302, and subsequent etchingprocess of said insulation film using dryetching or wetetching andresist stripping process. Unevenness may be form by exposure anddevelopment processes by use of photomask 200, using a film havingphotosensitive capabilities as said insulation film. As said insulationfilm, use is made of inorganic insulation film such as silicone oxidefilm, silicone nitride film, or organic insulation film such as acrylicresin, polyimide resin. Film deposition system includes, for example, asputter system, a chemical vapor deposition (CVD) system, and a spincoating system. An insulation film having photosensitive capabilitiesincludes an organic film such as acrylic resin and polyimide resin.However, the insulation film is not limited to thrdr resin films, andmay be one having photosensitive capabilities.

When fabricating reflective substrate 301 as described hereinabove,reflector fabrication device 130 sets the average pitch Pa ofdepressions or protrusions that occur on the surface of metal thin-film303 to: 1.0 μm≦Pa≦80 μm.

Reflective substrate 301 is fabricated by reflector fabrication device130 as described above. Unevenness is formed on a reflecting surfacemade up of the entire surface of metal thin-film 303 with dot patternsthat are randomly displaced within movable range R from regular basicpositions, as with photomask 200 shown in FIG. 6.

Liquid crystal fabrication device 140 is a device that fabricatesreflective liquid crystal display 300 using reflective substrate 301fabricated by reflector fabrication device 130. Portable terminalfabrication device 150 is a device that fabricates portable terminaldevice 400 using liquid crystal display 300 fabricated by liquid crystalfabrication device 140.

As described hereinabove, liquid crystal display 300 is fabricated byliquid crystal fabrication device 140, and includes reflective substrate301, liquid crystal layer 311, and transparent substrate 312. Morespecifically, base member 302 of reflective substrate 301 includesinsulating substrate 321, on the surface of which first and secondinterlayer insulating films 322 and 323 are successively formed, asshown in FIG. 7.

Various thin films are formed on the surface of insulating substrate 321and first interlayer insulating film 322, and driving circuits 324 suchas TFTs (thin-film transistors) are formed by these thin-films, for eachliquid crystal picture element 325. Metal thin-films 303 each connectedto driving circuit 324 are formed on the surface of second interlayerinsulating film 323 of base member 302 having such a construction foreach liquid crystal picture element 325. As previously described,unevenness is formed on the surface of second interlayer insulating film323 for each liquid crystal picture element 325, whereby unevenness isalso produced on the entire surface of metal thin-film 303.

Second interlayer insulating film 323 is constituted by an insulationfilm having one or more layers, and use is made of inorganic insulationfilm such as silicone oxide film and silicone nitride film or organicinsulation film such as acrylic resin and polyimide resin. Filmdeposition system includes, a sputter system, a chemical vapordeposition (CVD), and a spin coating system.

Transparent substrate 312 having transparent electrodes 326 formed onits entire back surface is integrally monolithically mounted on thesurface of reflective substrate 301 having such construction through aframe spacer member (not shown). The space between transparent substrate312 and reflective substrate 301 is then filled with liquid crystallayer 311.

As shown in FIG. 8, liquid crystal display 300 having this constructionis mounted in an opening of main housing 401 of portable terminal device400, which is a mobile telephone, and is exposed to the outside from theopening. Keyboard 402, microphone 403, and speaker 404 are also mountedin this main housing 401 so as to be exposed to the outside. A wirelesscommunication unit, battery, and so on are accommodated inside mainhousing 401 (not shown).

The operations of pattern generator 100, photomask fabrication device120, photomask 200, photo member fabrication device 130, reflectivesubstrate 301, liquid crystal fabrication device 140, liquid crystaldisplay 300, portable terminal fabrication device 150, and portableterminal device 400 having the above-described constructions will bedescribed hereinbelow in order.

As shown in FIG. 9, when pattern data is generated by pattern generator100, input guidance for switching data, the number of coordinates, basicpitch P, movable range R, and dot diameter D (or line width W) are firstdisplayed on display unit 18 in Step 501. The operator therefore entersthese data by manipulating the keyboard.

When pattern generator 100 determines that each of the above-describedrequired data has been entered to data entry unit 11 in Step 502, entryconfirmation unit 12 determines in Step 503 whether basic pitch P,movable range R, and dot diameter D (or line width W) that have beenentered satisfy the relationship P≧2R+D (or W). If it is determined thatthe data do not satisfy the relationship, a guidance message such as“The relationship between basic pitch P, movable range R, and dotdiameter D (or line width W) is inappropriate. Should processingcontinue? Y/N” is displayed on display unit 18 in Step 504.

In Step 505, the operator then selects either to correct the data entryor to continue processing the data and directs the selection to patterngenerator 100. When correction of entry is designated, pattern generator100 again executes the previously described processing of Steps 501-503.If the continuation of processing is designated, the data entry isconfirmed and processing proceeds to Step 506.

In Step 506, array generation unit 13 of pattern generator 100, inaccordance with entered basic pitch P, arranges base coordinates at thepositions of the vertices of pseudo equilateral triangles in which onlythe even-numbered rows of coordinate positions that have been arrangedin columns and rows are displaced half the basic pitch P in the columndirection, as shown in FIG. 2A.

Random number generator 14 next generates random numbers in Step 507.Coordinate displacement unit 15 then generates data of a multiplicity ofdisplaced coordinates by using the random numbers to randomly displaceeach of the multiplicity of base coordinates that have been regularlyarranged. At this time, the range of displacement is limited withinrange R entered by data entry unit 11, as shown in FIGS. 2B and 2C.

When generating displaced coordinates in this way, however, coordinatedisplacement unit 15 also generates a distribution graph of thedisplacements of the displaced coordinates as shown in FIG. 3 andcontrols the displacement of base coordinates such that half-width Hsatisfies the relationship 0.3 P≦H≦0.9 P in Step 509.

It is next determined in Step 510 whether the switching data designatedots. If the designation is for dots, pattern data are generated inwhich a dot pattern with dot diameter D are arranged at each of themultiplicity of displaced coordinates as shown in FIG. 2D in Step 511.If lines are designated, pattern data are generated in which a linepattern with line width W is arranged at each side of a hexagon thattakes as vertices the six displaced coordinates that are positionedaround a single displaced coordinate, as shown in FIG. 4.

The pattern data thus generated are displayed on display unit 18 in Step513. The operator checks the displayed pattern data and, from keyboard10, instructs pattern generator 100 whether to confirm or amend thepattern data in Step 514. When instructions to amend are entered,pattern generator 100 repeats the processing of the above-describedSteps 501-513. When instructions to confirm are entered, data outputunit 17 sends the pattern data to a data processor (not shown) ofphotomask fabrication device 120 in Step 515.

Photomask fabrication device 120 forms light-transmitting portions 202on mask material 201 by photoetching with the pattern data generated bypattern generator 100 to fabricate photomask 200 as shown in FIG. 6. Fordot-type photomask 200 a, light-transmitting portions 202 are formedwith a dot pattern with dot diameter D at each of a multiplicity ofdisplaced coordinates as shown in FIG. 6A, these displaced coordinateshaving been obtained by randomly displacing within movable range R eachof regular base coordinates. For a line-type photomask 200 b, on theother hand, light-transmitting portions 202 are formed with a linepattern with line width W at each side of hexagons as shown in FIG. 6B,these hexagons taking as vertices the six displaced coordinates that arepositioned around single displaced coordinate.

In reflector fabrication device 130, photomask 200 thus fabricated isloaded in an exposure device (not shown) and is used in the photoetchingof the surface of base member 302. Base member 302 constitutes a portionof liquid crystal display 300 as previously described, and photoetchingby means of photomask 200 is therefore carried out for the position ofeach liquid crystal picture element.

Metal thin-film 303, which is to constitute the picture elementelectrodes, is formed at the position of each liquid crystal pictureelement of base member 302 in which unevenness has been formed by thephotoetching. This results in the generation of unevenness on thesurface of this metal thin-film 303 that is identical to that on thesurface of base part 302. That is, metal thin-film 303 is formed at theposition of each liquid crystal picture element on reflective substrate301, and random unevenness is formed with the same dot pattern or linepattern as on photomask 200 on each of the surfaces of the multiplicityof metal thin-films 303.

Liquid crystal fabrication device 140 mounts transparent substrate 312at a predetermined spacing on the surface of reflective substrate 301thus fabricated, and interpose liquid crystal layer 311 betweenreflective substrate 301 and transparent substrate 312 to formreflective liquid crystal display 300. Portable terminal fabricationdevice 150 fabricates portable terminal device 400 using liquid crystaldisplay 300 thus fabricated.

With random unevenness formed on the surface of metal thin-film 303 foreach liquid crystal picture element on reflective substrate 301, metalthin-film 303, which is immersed in liquid crystal layer 311, canreflect incident light with good characteristics, rendering theviewability of a displayed image on liquid crystal display 300excellent.

Moreover, the unevenness formed on the surface of metal thin-film 303 ofthis reflective substrate 301 is formed corresponding to each of amultiplicity of displaced coordinates obtained by random displacement ofeach of regular base coordinates. No overlapping or excessive distanceoccurs between points of unevenness because this random displacement islimited within movable range R, and because the relationship betweenbasic pitch P, movable range R, and dot diameter D (or line width W)satisfies the condition P≦2R+D (or W). In particular, when theunevenness of reflective substrate 301 is formed with line patterns,unevenness in line form is formed at each side of hexagons, making thereflection characteristics particularly good.

Further, the half-width H of the pitch distribution graph of thesedepressions or protrusions satisfies the condition 0.3 Pa≦H≦0.9 Pa andthe average pitch Pa of the depressions or protrusions satisfies thecondition 1.0 μm≦Pa≦80 μm. As a result, the reflection characteristicsof reflective substrate 301 of liquid crystal display 300 isparticularly good and an image can be displayed with excellentviewability without using a backlight.

For this reason, portable terminal device 400 has no need for abacklight, and the entire device can therefore be made smaller andlighter and the productivity of the device can be improved. Even if abacklight is provided, the amount of time the backlight must be used canbe reduced, making the batteries smaller and providing power for alonger time period.

As discussed hereinabove, pattern generator 100 generates pattern datain which dot patterns or line patterns are randomly displaced within amovable range R from regular base coordinates to thereby preventoverlapping or excessive distance between the dot patterns or linepatters by movable range R. In particular, the base coordinates can berandomly displaced by simple data processing because the basecoordinates are displaced in accordance with random numbers within amovable range R.

Further, when the pattern data are produced by line patterns, a linepattern with line width W are arranged at each side of hexagons thattake displaced coordinates as vertices. This results in excellentreflection characteristics when the pattern data are employed to formunevenness on the reflecting surface of reflective substrate 301 ofreflective liquid crystal display 300.

Moreover, confirming that basic pitch P, movable range R, and dotdiameter D (or line width W) that are entered satisfy the conditionP≧2R+D (or W) allows the reliable generation of pattern data in whichadjacent dot patterns or line patterns do not overlap.

Further, base coordinates are displaced such that the half-width H ofthe distribution graph the displacement pitch of the displacedcoordinates satisfies the condition 0.3 P≦H≦0.9 P. This results inexcellent reflection characteristics when the pattern data are employedto form unevenness on the reflecting surface of reflective substrate 301of reflective liquid crystal display 300.

In addition, as the basic pattern of unevenness of reflective substrate301 of liquid crystal display 300, base coordinates can be arranged by asimple process at the positions of the vertices of pseudo equilateraltriangles because the base coordinates are arranged at positions suchthat even-numbered rows of coordinate positions are displaced, byone-half the basic pitch P in a column direction relative toodd-numbered rows of coordinate positions.

It is to be noted that because the base coordinates of pseudoequilateral triangles that have been thus generated from coordinates ofsquares have different spacing in the horizontal direction and vertical(diagonal) direction, the reflection characteristics also differ for thehorizontal and vertical directions of reflective substrate 301 thatcorresponds to these pattern data. On the other hand, since displaycharacteristics such as the angle of field typically differ in thevertical and horizontal directions of liquid crystal layer 311 of liquidcrystal display 300, the viewability of liquid crystal display 300 canbe further improved by making the directivity of the displaycharacteristics of this liquid crystal layer 311 correspond to thedirectivity of the reflection characteristics of reflective substrate301.

Photomask fabrication device 120 fabricates photomask 200 using patterndata generated by pattern generator 100. This makes it possible tofabricate photomask 200 that can form unevenness having excellentreflection characteristics on the reflecting surface of reflectivesubstrate 301 of reflective liquid crystal display 300.

Photomask 200 thus fabricated has either light-transmitting portions 202or light-blocking portions with dot patterns with dot diameter D at eachof a multiplicity of displaced coordinates that are derived by randomlydisplacing, within movable range R, each of a multiplicity of basecoordinates that have been regularly arranged according to basic pitchP. This makes it possible to form unevenness having excellent reflectioncharacteristics on the reflecting surface of reflective substrate 301 ofreflective liquid crystal display 300, as described hereinabove.

Reflector fabrication device 130 forms unevenness on the reflectingsurface of reflective substrate 301 by means of photoetching thatemploys photomask 200 fabricated by photomask fabrication system 120.This makes it possible to fabricate reflective substrate 301 ofreflective liquid crystal display 300 having excellent reflectioncharacteristics as previously described.

Liquid crystal fabrication device 140 fabricates liquid crystal display300 using reflective substrate 301 fabricated by reflector fabricationdevice 130, resulting in liquid crystal display 300 having excellentviewability.

Portable terminal fabrication device 150 fabricates portable terminaldevice 400 using liquid crystal display 300 fabricated by liquid crystalfabrication device 140, resulting in portable terminal device 400 havinga display with excellent viewability.

The present invention is not limited to the above-described embodimentand may take the form of the following modifications without departingfrom the scope of the invention.

In the above-described embodiment, an example was described in whichpattern generator 100 uses a circular shape as a dot pattern. However,the dot pattern may be of ellipse, a shape encircled by a curve, orpolygon such as triangle, quadrilateral, pentagon, and hexagon, and maybe of a separate shape. Dot pattern data may be produced by arrangingdot patterns at at least a portion of the displaced coordinates producedby coordinate displacement unit 15.

In the above-described embodiment, as a line pattern, pattern data wasproduced by arranging a line pattern with a line width at each side of apredetermined polygon that takes as vertices all or a portion ofdisplaced coordinates generated by coordinate displacement unit 15.However, a portion of line patterns may be arranged at all or a portionof the displaced coordinates.

In the above-described embodiment, an example was described in whichpattern generator 100 generates pattern data using only one of dotpatterns and line patterns. However, when line patterns are arranged atthe positions of each side of a hexagon that takes six displacedcoordinates as vertices as previously described, an unused displacedcoordinate is located at the center of the hexagon, and a dot patternmay be positioned at this displaced coordinate.

In the above-described embodiment, an example was described in which aline pattern with a line width W at each side of a polygon that takes asvertices all or a portion of a multiplicity of displaced coordinates.However, the line pattern may not be a straight line, and may be acurved line. The curved line may be of plural types. For example, curvedlines are generated in accordance with predetermined functions with allor a portion of displaced coordinates generated by coordinatedisplacement unit 15 as a start point to arrange line patterns.

In the above-described embodiment, a case was described in which basecoordinates were arranged at positions derived by displacing, byone-half the basic pitch P in the column direction, only even-numberedrows of coordinate positions relative to odd-numbered rows of coordinateportions, whereby base coordinates were arranged by a simple process atthe positions of the vertices of pseudo equilateral triangles. However,the base coordinates may also be simply arranged in, for example, rowsand columns without displacing in this way.

As the method of displacing base coordinates within a movable range R inaccordance with random numbers in the above-described embodiment, a casewas described in which the direction and distance of displacement of abase coordinate were generated by two random numbers. However, themovable range may be taken as a rectangle and displacement distances inthe vertical and horizontal directions may be generated by two randomnumbers.

As the method of generating displaced coordinates from base coordinatesin the above-described embodiment, a case was described in which allbase coordinates were randomly displaced. However, since data can begenerated even if, for example, only a portion of the base coordinatesare displaced, it is possible to randomly displace only odd-numberedrows and not displace even-numbered rows.

In the above-described embodiment, a case was described in which basecoordinates were randomly displaced to generate displaced coordinatesthat are randomly arranged in two dimensions. However, as an example,displaced coordinates may also be generated without using basecoordinates by using random numbers that are generated two at a time asx and y coordinates.

Further, in the above-described embodiment, an example was described inwhich reflector fabrication device 130 uses high-transmitting portion202 in the form of a dot pattern as shown in FIG. 6A, and light-blockingportion 201 in the form of a line pattern as shown in FIG. 6B, as aphotomask fabricated by photomask fabrication device 120. However, theline pattern shown in FIG. 6B may be light-transmitting portion 202, andthe dot pattern shown in FIG. 6A may be light-blocking portion 201,which constitute a reversed mask.

Photomask 200 is fabricated by photomask fabrication device 120 asdescribed above, and has light-transmitting portions 202 formed with dotpatterns with dot diameter D at each of the multiplicity of thedisplaced coordinates derived by displacing within the movable range Weach of the multiplicity of the basic coordinates regularly arranged inaccordance with the basic pitch as shown in FIG. 5A.

An example was described in which unevenness are formed on reflectivesubstrate 301. However, for example, reflector fabrication device 130may acquire pattern data directly from pattern generator 100, making itpossible to form unevenness on reflector substrate 301 without usingphotomask 200.

In the above-described embodiment, a case was described in whichreflector fabrication device 130 form unevenness on reflective substrate301 using photomask 200 fabricated by photomask fabrication device 120according to pattern data generated by pattern generator 100. However,reflector fabrication device 130 may, for example, form unevenness onreflective substrate 301 without using photomask 200 by directlyacquiring pattern data from pattern generator 100.

In the above-described embodiment, a case was described in whichunevenness was formed on the surface of base part 302 of reflectivesubstrate 301 by means of photolithography in accordance with patterndata, following which metal thin-film 303 was formed on base member 302,whereby unevenness was produced on the surface of metal thin-film 303that corresponds to the pattern data. However, unevenness thatcorresponds to the pattern data may be formed by photolithography on thesurface of metal thin-film (not shown) that is grown on the surface ofbase member 302.

In the above-described embodiment, a case was described in which, byforming unevenness that corresponds to pattern data on the surface ofbase part 302 at the position of each liquid crystal picture element ofliquid crystal display 300, unevenness was produced on the entiresurface of metal thin-film 303 for each liquid crystal picture element.However, unevenness may be formed on the entire surface of base part302, or alternatively, unevenness may be produced on only a portion ofthe surface of metal thin-film 303.

In the above-described embodiment, a case was described in which eachportion of pattern generator 100 was constituted by hardware. However, aprogram for realizing the functions of pattern generator 100 may berecorded on a computer-readable recording medium, and the programrecorded on the recording medium may then be executed by a computer. Thecomputer-readable recording medium refers to a recording medium such asa floppy disk, a magneto-optic disk, a CD-ROM or a storage unit such asa hard disk that is incorporated in a computer system. Thecomputer-readable recording medium further includes a medium that hold aprogram for a fixed time period such as a volatile memory within thecomputer system that is the server in such cases.

Other embodiments of the invention will be apparent to those skilled inthe art from a consideration of the specification or practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with the true scope and spiritof the invention being indicated by the following claims.

1. A device for generating pattern data for unevenness that is randomlyarranged on a reflecting surface, said device comprising: coordinatedisplacement means for generating a multiplicity of displacedcoordinates that are randomly displaced in two dimensions with alimitation on the arrangement of patterns to prevent overlap orexcessive distance between patterns; and pattern generation means forarranging predetermined line patterns according to at least a portion ofor all of said displaced coordinates generated by said coordinatedisplacement means to generate the pattern data for unevenness that israndomly arranged on the reflecting surface, wherein said coordinatedisplacement means includes means for displacing said base coordinatessuch that half width H of a distribution graph of the displacements ofsaid displaced coordinates satisfies the relationship with a basic pitchP: 0.3 P≦H≦0.9 P.
 2. A device according to claim 1, further comprisingrandom number generation means for generating random numbers; whereinsaid coordinate displacement means displaces said base coordinatesaccording to random numbers generated by said random number generationmeans.
 3. A device for generating pattern data for unevenness that israndomly arranged on a reflecting surface, said device comprising: dataentry means for entering a basic pitch, a movable range, and a linewidth; array generation means for regularly arranging a multiplicity ofbase coordinates in two dimensions in accordance with said basic pitchentered by said data entry means; coordinate displacement means forrandomly displacing within said movable range at least a portion of saidbase coordinates arranged by said array generation means to generate amultiplicity of displaced coordinates; pattern generation means forarranging a line pattern with said line width at each side of aplurality of predetermined polygons that take as vertices at least aportion of said displaced coordinates generated by said coordinatedisplacement means to generate the pattern data; and entry confirmationmeans for determining whether or not said basic pitch P, said movablerange R, and said line width W entered by said data entry means satisfythe relationship:P≧2R+W.
 4. A device according to claim 3, further comprising randomnumber generation means for generating random numbers; wherein saidcoordinate displacement means displaces said base coordinates accordingto random numbers generated by said random number generation means.
 5. Adevice according to claim 3, wherein said polygons are hexagons.
 6. Adevice according to claim 3, wherein said coordinate displacement meansincludes means for displacing said base coordinates such that half widthH of a distribution graph of the displacements of said displacedcoordinates satisfies the relationship with said basic pitch P: 0.3P≦H≦0.9 P.
 7. A device for generating pattern data for unevenness thatis randomly arranged on a reflecting surface, said device comprising:data entry means for entering a basic pitch, a movable range, and a linewidth; array generation means for regularly arranging a multiplicity ofbase coordinates in two dimensions in accordance with said basic pitchentered by said data entry means; coordinate displacement means forrandomly displacing within said movable range at least a portion of saidbase coordinates arranged by said array generation means to generate amultiplicity of displaced coordinates; and pattern generation means forarranging a line pattern with said line width at each side of aplurality of predetermined polygons that take as vertices at least aportion of said displaced coordinates generated by said coordinatedisplacement means to generate the pattern data for unevenness that israndomly arranged on the reflecting surface, wherein said arraygeneration means includes means for arranging said base coordinates inpositions such that even numbered rows of the base coordinates aredisplaced by one half of said basic pitch in the column directionrelative to odd numbered rows of the base coordinates.
 8. Acomputer-readable storage medium storing a computer program for causinga computer to execute processes for generating pattern data forunevenness that is randomly arranged on a reflecting surface, saidcomputer program comprising executable code that provides: a firstcommand set for entering a pitch, a movable range, and a line width; asecond command set for regularly arranging a multiplicity of basecoordinates in two dimensions in accordance with said basic pitchentered by said first command set; a third command set for randomlydisplacing within said movable range at least a portion of said basecoordinates arranged by said second command set, wherein the thirdcommand set provides for displacing said base coordinates such that halfwidth H of a distribution graph of the displacements of said displacedcoordinates satisfies the relationship with said basic pitch P: 0.3P≦H≦0.9 P; and a fourth command set for arranging a line pattern withsaid line width at each side of a plurality of predetermined polygonsthat take as vertices at least a portion of said displaced coordinatesgenerated by said third command set to generate the pattern data forunevenness that is randomly arranged on the reflecting surface.
 9. Acomputer-readable storage medium storing a computer program for causinga computer to execute processes for generating pattern data forunevenness that is randomly arranged on a reflecting surface, saidcomputer program comprising executable code that provides: a firstcommand set for entering a pitch, a movable range, and a line width; asecond command set for regularly arranging a multiplicity of basecoordinates in two dimensions in accordance with said basic pitchentered by said first command set; a third command set for randomlydisplacing within said movable range at least a portion of said basecoordinates arranged by said second command set; and a fourth commandset for arranging a line pattern with said line width at each side of aplurality of predetermined polygons that take as vertices at least aportion of said displaced coordinates generated by said third commandset to generate the pattern data for unevenness that is randomlyarranged on the reflecting surface, wherein the line pattern is arrangedaccording to the basic pitch P, the movable range R, and the line widthW satisfying the relationship:P≦2R+W.
 10. A computer-readable storage medium storing a computerprogram for causing a computer to execute processes for generatingpattern data for unevenness that is randomly arranged on a reflectingsurface, said computer program comprising executable code that provides:a first command set for entering a pitch, a movable range, and a linewidth; a second command set for regularly arranging a multiplicity ofbase coordinates in two dimensions in accordance with said basic pitchentered by said first command set, wherein the second command setprovides for arranging said base coordinates in positions such that evennumbered rows of the base coordinates are displaced by one half of saidbasic pitch in the column direction relative to odd numbered rows of thebase coordinates; a third command set for randomly displacing withinsaid movable range at least a portion of said base coordinates arrangedby said second command set; and a fourth command set for arranging aline pattern with said line width at each side of a plurality ofpredetermined polygons that take as vertices at least a portion of saiddisplaced coordinates generated by said third command set to generatethe pattern data for unevenness that is randomly arranged on thereflecting surface.